Generally, the widely-used peripheral input device of a computer system includes for example a mouse, a keyboard, a trackball, or the like. Via the keyboard, characters or symbols can be directly inputted into the computer system. As a consequence, most users and most manufacturers of input devices pay much attention to the development of keyboards. As known, a keyboard with scissors-type connecting elements is one of the widely-used keyboards.
Hereinafter, a key structure with a scissors-type connecting element of a conventional keyboard will be illustrated with reference to FIG. 1. FIG. 1 is a schematic side cross-sectional view illustrating a conventional key structure. As shown in FIG. 1, the conventional key structure 1 comprises a keycap 11, a scissors-type connecting element 12, a rubbery elastomer 13, a membrane switch circuit member 14 and a base 15. The keycap 11, the scissors-type connecting element 12, the rubbery elastomer 13 and the membrane switch circuit member 14 are supported by the base 15. The scissors-type connecting element 12 is used for connecting the base 15 and the keycap 11.
The membrane switch circuit member 14 comprises plural key intersections (not shown). When one of the plural key intersections is triggered, a corresponding key signal is generated. The rubbery elastomer 13 is disposed on the membrane switch circuit member 14. Each rubbery elastomer 13 is aligned with a corresponding key intersection. When the rubbery elastomer 13 is depressed, the rubbery elastomer 13 is subjected to deformation to push the corresponding key intersection of the membrane switch circuit member 14. Consequently, the corresponding key signal is generated.
The scissors-type connecting element 12 is arranged between the base 15 and the keycap 11, and the base 15 and the keycap 11 are connected with each other through the scissors-type connecting element 12. The scissors-type connecting element 12 comprises a first frame 121 and a second frame 122. A first end of the first frame 121 is connected with the keycap 11. A second end of the first frame 121 is connected with the base 15. The rubbery elastomer 13 is enclosed by the scissors-type connecting element 12. Moreover, the first frame 121 comprises a first keycap post 1211 and a first base post 1212. The first frame 121 is connected with the keycap 11 through the first keycap post 1211. The first frame 121 is connected with the base 15 through the first base post 1212. The second frame 122 is combined with the first frame 121. A first end of the second frame 122 is connected with the base 15. A second end of the second frame 122 is connected with the keycap 11. Moreover, the second frame 122 comprises a second keycap post 1221 and a second base post 1222. The second frame 122 is connected with the keycap 11 through the second keycap post 1221. The second frame 122 is connected with the base 15 through the second base post 1222.
The operations of the conventional key structure 1 in response to the depressing action of the user will be illustrated as follows. Please refer to FIG. 1 again. When the keycap 11 is depressed by the user, the keycap 11 is moved downwardly to push the scissors-type connecting element 12 in response to the depressing force. As the keycap 11 is moved downwardly relative to the base 15, the keycap 11 pushes the corresponding rubbery elastomer 13. At the same time, the rubbery elastomer 13 is subjected to deformation to push the membrane switch circuit member 14 and trigger the corresponding key intersection of the membrane switch circuit member 14. Consequently, the membrane switch circuit member 14 generates a corresponding key signal. When the keycap 11 is no longer depressed by the user, no external force is applied to the keycap 11, and the rubbery elastomer 13 is no longer pushed by the keycap 11. In response to the elasticity of the rubbery elastomer 13, the rubbery elastomer 13 is restored to its original shape to provide an upward elastic restoring force. Consequently, the keycap 11 is returned to its original position where it is not depressed.
Recently, the general trends of designing electronic devices and their peripheral devices are toward slimness, light weightiness an easy portability. Consequently, keyboards and other peripheral devices need to meet the requirements of slimness. For achieving this purpose, the manufacturers make efforts in minimizing the thicknesses of some or all components of the key structure. Under this circumstance, the structural strength of the key structure is impaired, and thus the key structure is easily damaged. Moreover, the tactile feel of depressing the key structure is deteriorated.
Therefore, there is a need of providing a key structure with slimness and increased structured strength.